networking - Hairpinning in Linux

I have a router in which I installed a Linux system.

I want my router to support NAT hairpinning.

Does a such feature exists in Kernel Linux? If yes how to activate it? Are there a patch to apply it on my kernel to support hairpinning?

Hairpinning explanation from Wikipedia:

Let us consider a private network with the following:

    Gateway address: 192.168.0.1
    Host 1: 192.168.0.5
    Host 2: 192.168.0.7

    The gateway has an external IP : 192.0.2.1
    Host 1 runs a P2P application P1 on its port 12345 which is externally mapped to 4444.
    Host 2 runs a P2P application P2 on its port 12345 which is externally mapped to 5555.

If the NAT device supports hairpinning, then P1 application can connect to the P2 application using the external endpoint 192.0.2.1:5555.
If not, the communication will not work.